From: Marek Olšák <marek.ol...@amd.com>
Discussion: https://bugs.freedesktop.org/show_bug.cgi?id=83510#c8
---
src/gallium/drivers/radeonsi/si_shader.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/src/gallium/drivers/radeonsi/si_shader.c
b/src/gallium/drivers/radeonsi/si_shader.c
index 973bac2..e0799c9 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -2744,6 +2744,32 @@ static int si_generate_gs_copy_shader(struct si_screen
*sscreen,
return r;
}
+/**
+ * This emulates V_RCP_LEGACY_F32, which has the following rule for division
+ * by zero: 1 / 0 = 0
+ *
+ * V_RCP_F32(x) = 1 / x
+ * V_RCP_LEGACY_F32(x) = (x != +-0) ? V_RCP_F32(x) : 0.
+ */
+static void si_llvm_emit_rcp_legacy(const struct lp_build_tgsi_action * action,
+ struct lp_build_tgsi_context * bld_base,
+ struct lp_build_emit_data * emit_data)
+{
+ LLVMValueRef cmp =
+ lp_build_cmp(&bld_base->base,
+ PIPE_FUNC_NOTEQUAL,
+ emit_data->args[0],
+ bld_base->base.zero);
+
+ LLVMValueRef div =
+ lp_build_emit_llvm_binary(bld_base, TGSI_OPCODE_DIV,
+ bld_base->base.one,
+ emit_data->args[0]);
+
+ emit_data->output[emit_data->chan] =
+ lp_build_select(&bld_base->base, cmp, div, bld_base->base.zero);
+}
+
int si_shader_create(struct si_screen *sscreen, struct si_shader *shader)
{
struct si_shader_selector *sel = shader->selector;
@@ -2798,6 +2824,7 @@ int si_shader_create(struct si_screen *sscreen, struct
si_shader *shader)
bld_base->op_actions[TGSI_OPCODE_MIN].emit =
build_tgsi_intrinsic_nomem;
bld_base->op_actions[TGSI_OPCODE_MIN].intr_name =
"llvm.minnum.f32";
}
+ bld_base->op_actions[TGSI_OPCODE_RCP].emit = si_llvm_emit_rcp_legacy;
si_shader_ctx.radeon_bld.load_system_value = declare_system_value;
si_shader_ctx.tokens = sel->tokens;
--
2.1.0
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